Replacing Switchmaster 300 Timer on Ocean 80-FF Style Boiler

[pmoore31]

I wonder if anyone could please help.

I currently own an old Ocean 80-FF Style combi boiler which is working fine at the moment. The timer is an old Switchmaster 300 (the brown type with a dial on the left and a switch on the right of it. this times our heating from the combi boiler. (i have search through the internet to find some instructions for this but cant find any)

I wanted to update the timer to a digital one and thought it would be a good idea to buy one off ebay.

I purchased a Centaurplus C27

http://www.horstmann.co.uk/downloads/ElectronicDocuments/Central-Heating/C27-InstallerGuide.pdf

Which came with some instructions I didn’t understand? I noticed they both had the same wiring plate inside which is marked N L 1 2 3 4.

The swichtmaster also has a wire connected fom N to 2 and a wire from L to 4

I thought I would be clever and just take the wires off the Switchmaster and place them of the Centaurplus in exactly the same order.

All this seemed to do is blow a fuse in the boiler socket!! Is it not that simple?

Looking a bit closer it looks like the Switchmaster is a single channel and the Centaurplus is a 2 channel.
Should I buy a single channel switch and copy the wiring? Will this work on a Centaurplus c17 http://www.horstmann.co.uk/downloads/ElectronicDocuments/Central-Heating/C17-UserGuide.pdf

Sorry to sound so dumb but could somebody please give me some advice.

Many Thanks

Phil
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[ChrisR]

Your c27 doesn't provide the electrically independent ("volt free") contacts required by the boiler. Though you might be able to "get away with it" you should have bought the single channel timer, which has them.
You could call Alpha who just might say it's ok.

 

[pmoore31]

Many Thanks ChrisR. I think I will purchase a single channel and resell the 2 channel on ebay. Again thanks for your help

Phil

 

[pmoore31]

Should have asked..... do you think a Centauraplus C17 single channel will have the same wiring sequence i.e L N 1 2 3 4 as the switchmaster 300 or will i have to change the wiring sequence as i am thinking of buying a Centaurplus C17